The chemical structure of the mannans of antigenic factor 9-expressing yeast, Candida famata and Candida saitoana, was analyzed by acetolysis and NMR. The structural study of the oligosaccharides and mannans using one- and two-dimensional NMR indicated that the mannan of C. saitoana contains a third type of β-1,2-linked mannose unit. On the other hand, the mannan of C. famata does not contain any β-1,2-linked mannose units. The mannan of C. saitoana gave two groups of β-1,2 linkage-containing oligosaccharides by acetolysis. One contains one β-1,2-linked mannose unit and the other contains two consecutive β-1,2-linked mannose units at the nonreducing terminal. The inhibition of the reactivity of factor 9 serum on an enzyme- linked immunosorbent assay (ELISA) with these oligosaccharides indicated that the inhibition activity of the former oligosaccharide is 1/20 of that of the latter ones. The ELISA of the mannans of Candida guilliermondii, C. saitoana, and Saccharomyces kluyveri, all of which contain the third type of β-1,2- linked mannose unit, indicated that Manβ1 → 2Manβ1 → 2Manα1 → 3Manα1 → works as the antigenic factor 9 but Manβ1 → 2Manα1 → 3Manα1 → weakly behaves as both antigenic factors 6 and 9. The epitope structures of the side chain oligosaccharides agreed well with that proposed from the 2D-HOHAHA spectra of the mannans. This result demonstrates the usefulness of the H-1- H-2-correlated cross-peak pattern, which was reported in a preceding paper (Shibata, N., Akagi, R., Hosoya, T., Kawahara, K., Suzuki, A., Ikuta, K., Kobayashi, H., Hisamichi, K., Okawa, Y., and Suzuki, S. (1996) J. Biol. Chem. 271, 9259-9266) for the determination of the epitope structure of Candida mannans without any chemical fragmentation.
ASJC Scopus subject areas
- Molecular Biology